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ae98043f | 1 | // SPDX-License-Identifier: GPL-2.0+ |
0bd49f94 RK |
2 | /* |
3 | * page.c - buffer/page management specific to NILFS | |
4 | * | |
5 | * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. | |
6 | * | |
4b420ab4 | 7 | * Written by Ryusuke Konishi and Seiji Kihara. |
0bd49f94 RK |
8 | */ |
9 | ||
10 | #include <linux/pagemap.h> | |
11 | #include <linux/writeback.h> | |
12 | #include <linux/swap.h> | |
13 | #include <linux/bitops.h> | |
14 | #include <linux/page-flags.h> | |
15 | #include <linux/list.h> | |
16 | #include <linux/highmem.h> | |
17 | #include <linux/pagevec.h> | |
5a0e3ad6 | 18 | #include <linux/gfp.h> |
0bd49f94 RK |
19 | #include "nilfs.h" |
20 | #include "page.h" | |
21 | #include "mdt.h" | |
22 | ||
23 | ||
4ce5c342 RK |
24 | #define NILFS_BUFFER_INHERENT_BITS \ |
25 | (BIT(BH_Uptodate) | BIT(BH_Mapped) | BIT(BH_NILFS_Node) | \ | |
26 | BIT(BH_NILFS_Volatile) | BIT(BH_NILFS_Checked)) | |
0bd49f94 RK |
27 | |
28 | static struct buffer_head * | |
29 | __nilfs_get_page_block(struct page *page, unsigned long block, pgoff_t index, | |
30 | int blkbits, unsigned long b_state) | |
31 | ||
32 | { | |
33 | unsigned long first_block; | |
34 | struct buffer_head *bh; | |
35 | ||
36 | if (!page_has_buffers(page)) | |
37 | create_empty_buffers(page, 1 << blkbits, b_state); | |
38 | ||
09cbfeaf | 39 | first_block = (unsigned long)index << (PAGE_SHIFT - blkbits); |
0bd49f94 RK |
40 | bh = nilfs_page_get_nth_block(page, block - first_block); |
41 | ||
42 | touch_buffer(bh); | |
43 | wait_on_buffer(bh); | |
44 | return bh; | |
45 | } | |
46 | ||
0bd49f94 RK |
47 | struct buffer_head *nilfs_grab_buffer(struct inode *inode, |
48 | struct address_space *mapping, | |
49 | unsigned long blkoff, | |
50 | unsigned long b_state) | |
51 | { | |
52 | int blkbits = inode->i_blkbits; | |
09cbfeaf | 53 | pgoff_t index = blkoff >> (PAGE_SHIFT - blkbits); |
c1c1d709 RK |
54 | struct page *page; |
55 | struct buffer_head *bh; | |
0bd49f94 RK |
56 | |
57 | page = grab_cache_page(mapping, index); | |
58 | if (unlikely(!page)) | |
59 | return NULL; | |
60 | ||
61 | bh = __nilfs_get_page_block(page, blkoff, index, blkbits, b_state); | |
62 | if (unlikely(!bh)) { | |
63 | unlock_page(page); | |
09cbfeaf | 64 | put_page(page); |
0bd49f94 RK |
65 | return NULL; |
66 | } | |
0bd49f94 RK |
67 | return bh; |
68 | } | |
69 | ||
70 | /** | |
71 | * nilfs_forget_buffer - discard dirty state | |
72 | * @inode: owner inode of the buffer | |
73 | * @bh: buffer head of the buffer to be discarded | |
74 | */ | |
75 | void nilfs_forget_buffer(struct buffer_head *bh) | |
76 | { | |
77 | struct page *page = bh->b_page; | |
ead8ecff | 78 | const unsigned long clear_bits = |
4ce5c342 RK |
79 | (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) | |
80 | BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) | | |
81 | BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected)); | |
0bd49f94 RK |
82 | |
83 | lock_buffer(bh); | |
ead8ecff | 84 | set_mask_bits(&bh->b_state, clear_bits, 0); |
84338237 | 85 | if (nilfs_page_buffers_clean(page)) |
0bd49f94 RK |
86 | __nilfs_clear_page_dirty(page); |
87 | ||
0bd49f94 RK |
88 | bh->b_blocknr = -1; |
89 | ClearPageUptodate(page); | |
90 | ClearPageMappedToDisk(page); | |
91 | unlock_buffer(bh); | |
92 | brelse(bh); | |
93 | } | |
94 | ||
95 | /** | |
96 | * nilfs_copy_buffer -- copy buffer data and flags | |
97 | * @dbh: destination buffer | |
98 | * @sbh: source buffer | |
99 | */ | |
100 | void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh) | |
101 | { | |
102 | void *kaddr0, *kaddr1; | |
103 | unsigned long bits; | |
104 | struct page *spage = sbh->b_page, *dpage = dbh->b_page; | |
105 | struct buffer_head *bh; | |
106 | ||
7b9c0976 CW |
107 | kaddr0 = kmap_atomic(spage); |
108 | kaddr1 = kmap_atomic(dpage); | |
0bd49f94 | 109 | memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size); |
7b9c0976 CW |
110 | kunmap_atomic(kaddr1); |
111 | kunmap_atomic(kaddr0); | |
0bd49f94 RK |
112 | |
113 | dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS; | |
114 | dbh->b_blocknr = sbh->b_blocknr; | |
115 | dbh->b_bdev = sbh->b_bdev; | |
116 | ||
117 | bh = dbh; | |
4ce5c342 | 118 | bits = sbh->b_state & (BIT(BH_Uptodate) | BIT(BH_Mapped)); |
0bd49f94 RK |
119 | while ((bh = bh->b_this_page) != dbh) { |
120 | lock_buffer(bh); | |
121 | bits &= bh->b_state; | |
122 | unlock_buffer(bh); | |
123 | } | |
4ce5c342 | 124 | if (bits & BIT(BH_Uptodate)) |
0bd49f94 RK |
125 | SetPageUptodate(dpage); |
126 | else | |
127 | ClearPageUptodate(dpage); | |
4ce5c342 | 128 | if (bits & BIT(BH_Mapped)) |
0bd49f94 RK |
129 | SetPageMappedToDisk(dpage); |
130 | else | |
131 | ClearPageMappedToDisk(dpage); | |
132 | } | |
133 | ||
134 | /** | |
135 | * nilfs_page_buffers_clean - check if a page has dirty buffers or not. | |
136 | * @page: page to be checked | |
137 | * | |
138 | * nilfs_page_buffers_clean() returns zero if the page has dirty buffers. | |
139 | * Otherwise, it returns non-zero value. | |
140 | */ | |
141 | int nilfs_page_buffers_clean(struct page *page) | |
142 | { | |
143 | struct buffer_head *bh, *head; | |
144 | ||
145 | bh = head = page_buffers(page); | |
146 | do { | |
147 | if (buffer_dirty(bh)) | |
148 | return 0; | |
149 | bh = bh->b_this_page; | |
150 | } while (bh != head); | |
151 | return 1; | |
152 | } | |
153 | ||
154 | void nilfs_page_bug(struct page *page) | |
155 | { | |
156 | struct address_space *m; | |
aa405b1f | 157 | unsigned long ino; |
0bd49f94 RK |
158 | |
159 | if (unlikely(!page)) { | |
160 | printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n"); | |
161 | return; | |
162 | } | |
163 | ||
164 | m = page->mapping; | |
aa405b1f RK |
165 | ino = m ? m->host->i_ino : 0; |
166 | ||
0bd49f94 RK |
167 | printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx " |
168 | "mapping=%p ino=%lu\n", | |
fe896d18 | 169 | page, page_ref_count(page), |
0bd49f94 RK |
170 | (unsigned long long)page->index, page->flags, m, ino); |
171 | ||
172 | if (page_has_buffers(page)) { | |
173 | struct buffer_head *bh, *head; | |
174 | int i = 0; | |
175 | ||
176 | bh = head = page_buffers(page); | |
177 | do { | |
178 | printk(KERN_CRIT | |
179 | " BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n", | |
180 | i++, bh, atomic_read(&bh->b_count), | |
181 | (unsigned long long)bh->b_blocknr, bh->b_state); | |
182 | bh = bh->b_this_page; | |
183 | } while (bh != head); | |
184 | } | |
185 | } | |
186 | ||
0bd49f94 RK |
187 | /** |
188 | * nilfs_copy_page -- copy the page with buffers | |
189 | * @dst: destination page | |
190 | * @src: source page | |
191 | * @copy_dirty: flag whether to copy dirty states on the page's buffer heads. | |
192 | * | |
7a65004b | 193 | * This function is for both data pages and btnode pages. The dirty flag |
0bd49f94 RK |
194 | * should be treated by caller. The page must not be under i/o. |
195 | * Both src and dst page must be locked | |
196 | */ | |
197 | static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty) | |
198 | { | |
199 | struct buffer_head *dbh, *dbufs, *sbh, *sbufs; | |
200 | unsigned long mask = NILFS_BUFFER_INHERENT_BITS; | |
201 | ||
202 | BUG_ON(PageWriteback(dst)); | |
203 | ||
204 | sbh = sbufs = page_buffers(src); | |
205 | if (!page_has_buffers(dst)) | |
206 | create_empty_buffers(dst, sbh->b_size, 0); | |
207 | ||
208 | if (copy_dirty) | |
4ce5c342 | 209 | mask |= BIT(BH_Dirty); |
0bd49f94 RK |
210 | |
211 | dbh = dbufs = page_buffers(dst); | |
212 | do { | |
213 | lock_buffer(sbh); | |
214 | lock_buffer(dbh); | |
215 | dbh->b_state = sbh->b_state & mask; | |
216 | dbh->b_blocknr = sbh->b_blocknr; | |
217 | dbh->b_bdev = sbh->b_bdev; | |
218 | sbh = sbh->b_this_page; | |
219 | dbh = dbh->b_this_page; | |
220 | } while (dbh != dbufs); | |
221 | ||
222 | copy_highpage(dst, src); | |
223 | ||
224 | if (PageUptodate(src) && !PageUptodate(dst)) | |
225 | SetPageUptodate(dst); | |
226 | else if (!PageUptodate(src) && PageUptodate(dst)) | |
227 | ClearPageUptodate(dst); | |
228 | if (PageMappedToDisk(src) && !PageMappedToDisk(dst)) | |
229 | SetPageMappedToDisk(dst); | |
230 | else if (!PageMappedToDisk(src) && PageMappedToDisk(dst)) | |
231 | ClearPageMappedToDisk(dst); | |
232 | ||
233 | do { | |
234 | unlock_buffer(sbh); | |
235 | unlock_buffer(dbh); | |
236 | sbh = sbh->b_this_page; | |
237 | dbh = dbh->b_this_page; | |
238 | } while (dbh != dbufs); | |
239 | } | |
240 | ||
241 | int nilfs_copy_dirty_pages(struct address_space *dmap, | |
242 | struct address_space *smap) | |
243 | { | |
244 | struct pagevec pvec; | |
245 | unsigned int i; | |
246 | pgoff_t index = 0; | |
247 | int err = 0; | |
248 | ||
86679820 | 249 | pagevec_init(&pvec); |
0bd49f94 | 250 | repeat: |
67fd707f | 251 | if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY)) |
0bd49f94 RK |
252 | return 0; |
253 | ||
254 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
255 | struct page *page = pvec.pages[i], *dpage; | |
256 | ||
257 | lock_page(page); | |
258 | if (unlikely(!PageDirty(page))) | |
259 | NILFS_PAGE_BUG(page, "inconsistent dirty state"); | |
260 | ||
261 | dpage = grab_cache_page(dmap, page->index); | |
262 | if (unlikely(!dpage)) { | |
263 | /* No empty page is added to the page cache */ | |
264 | err = -ENOMEM; | |
265 | unlock_page(page); | |
266 | break; | |
267 | } | |
268 | if (unlikely(!page_has_buffers(page))) | |
269 | NILFS_PAGE_BUG(page, | |
270 | "found empty page in dat page cache"); | |
271 | ||
272 | nilfs_copy_page(dpage, page, 1); | |
273 | __set_page_dirty_nobuffers(dpage); | |
274 | ||
275 | unlock_page(dpage); | |
09cbfeaf | 276 | put_page(dpage); |
0bd49f94 RK |
277 | unlock_page(page); |
278 | } | |
279 | pagevec_release(&pvec); | |
280 | cond_resched(); | |
281 | ||
282 | if (likely(!err)) | |
283 | goto repeat; | |
284 | return err; | |
285 | } | |
286 | ||
287 | /** | |
7a65004b | 288 | * nilfs_copy_back_pages -- copy back pages to original cache from shadow cache |
0bd49f94 RK |
289 | * @dmap: destination page cache |
290 | * @smap: source page cache | |
291 | * | |
f611ff63 | 292 | * No pages must be added to the cache during this process. |
0bd49f94 RK |
293 | * This must be ensured by the caller. |
294 | */ | |
295 | void nilfs_copy_back_pages(struct address_space *dmap, | |
296 | struct address_space *smap) | |
297 | { | |
298 | struct pagevec pvec; | |
299 | unsigned int i, n; | |
300 | pgoff_t index = 0; | |
0bd49f94 | 301 | |
86679820 | 302 | pagevec_init(&pvec); |
0bd49f94 | 303 | repeat: |
397162ff | 304 | n = pagevec_lookup(&pvec, smap, &index); |
0bd49f94 RK |
305 | if (!n) |
306 | return; | |
0bd49f94 RK |
307 | |
308 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
309 | struct page *page = pvec.pages[i], *dpage; | |
310 | pgoff_t offset = page->index; | |
311 | ||
312 | lock_page(page); | |
313 | dpage = find_lock_page(dmap, offset); | |
314 | if (dpage) { | |
f611ff63 | 315 | /* overwrite existing page in the destination cache */ |
1f5abe7e | 316 | WARN_ON(PageDirty(dpage)); |
0bd49f94 RK |
317 | nilfs_copy_page(dpage, page, 0); |
318 | unlock_page(dpage); | |
09cbfeaf | 319 | put_page(dpage); |
f611ff63 | 320 | /* Do we not need to remove page from smap here? */ |
0bd49f94 | 321 | } else { |
f611ff63 | 322 | struct page *p; |
0bd49f94 RK |
323 | |
324 | /* move the page to the destination cache */ | |
b93b0163 | 325 | xa_lock_irq(&smap->i_pages); |
f611ff63 MW |
326 | p = __xa_erase(&smap->i_pages, offset); |
327 | WARN_ON(page != p); | |
0bd49f94 | 328 | smap->nrpages--; |
b93b0163 | 329 | xa_unlock_irq(&smap->i_pages); |
0bd49f94 | 330 | |
b93b0163 | 331 | xa_lock_irq(&dmap->i_pages); |
f611ff63 MW |
332 | p = __xa_store(&dmap->i_pages, offset, page, GFP_NOFS); |
333 | if (unlikely(p)) { | |
334 | /* Probably -ENOMEM */ | |
0bd49f94 | 335 | page->mapping = NULL; |
f611ff63 | 336 | put_page(page); |
0bd49f94 RK |
337 | } else { |
338 | page->mapping = dmap; | |
339 | dmap->nrpages++; | |
340 | if (PageDirty(page)) | |
f611ff63 MW |
341 | __xa_set_mark(&dmap->i_pages, offset, |
342 | PAGECACHE_TAG_DIRTY); | |
0bd49f94 | 343 | } |
b93b0163 | 344 | xa_unlock_irq(&dmap->i_pages); |
0bd49f94 RK |
345 | } |
346 | unlock_page(page); | |
347 | } | |
348 | pagevec_release(&pvec); | |
349 | cond_resched(); | |
350 | ||
351 | goto repeat; | |
352 | } | |
353 | ||
8c26c4e2 VD |
354 | /** |
355 | * nilfs_clear_dirty_pages - discard dirty pages in address space | |
356 | * @mapping: address space with dirty pages for discarding | |
357 | * @silent: suppress [true] or print [false] warning messages | |
358 | */ | |
359 | void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent) | |
0bd49f94 RK |
360 | { |
361 | struct pagevec pvec; | |
362 | unsigned int i; | |
363 | pgoff_t index = 0; | |
364 | ||
86679820 | 365 | pagevec_init(&pvec); |
0bd49f94 | 366 | |
67fd707f JK |
367 | while (pagevec_lookup_tag(&pvec, mapping, &index, |
368 | PAGECACHE_TAG_DIRTY)) { | |
0bd49f94 RK |
369 | for (i = 0; i < pagevec_count(&pvec); i++) { |
370 | struct page *page = pvec.pages[i]; | |
0bd49f94 RK |
371 | |
372 | lock_page(page); | |
8c26c4e2 | 373 | nilfs_clear_dirty_page(page, silent); |
0bd49f94 RK |
374 | unlock_page(page); |
375 | } | |
376 | pagevec_release(&pvec); | |
377 | cond_resched(); | |
378 | } | |
379 | } | |
380 | ||
8c26c4e2 VD |
381 | /** |
382 | * nilfs_clear_dirty_page - discard dirty page | |
383 | * @page: dirty page that will be discarded | |
384 | * @silent: suppress [true] or print [false] warning messages | |
385 | */ | |
386 | void nilfs_clear_dirty_page(struct page *page, bool silent) | |
387 | { | |
388 | struct inode *inode = page->mapping->host; | |
389 | struct super_block *sb = inode->i_sb; | |
390 | ||
dc33f5f3 | 391 | BUG_ON(!PageLocked(page)); |
8c26c4e2 | 392 | |
d6517deb | 393 | if (!silent) |
a1d0747a JP |
394 | nilfs_warn(sb, "discard dirty page: offset=%lld, ino=%lu", |
395 | page_offset(page), inode->i_ino); | |
8c26c4e2 VD |
396 | |
397 | ClearPageUptodate(page); | |
398 | ClearPageMappedToDisk(page); | |
399 | ||
400 | if (page_has_buffers(page)) { | |
401 | struct buffer_head *bh, *head; | |
ead8ecff | 402 | const unsigned long clear_bits = |
4ce5c342 RK |
403 | (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) | |
404 | BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) | | |
405 | BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected)); | |
8c26c4e2 VD |
406 | |
407 | bh = head = page_buffers(page); | |
408 | do { | |
409 | lock_buffer(bh); | |
d6517deb | 410 | if (!silent) |
a1d0747a JP |
411 | nilfs_warn(sb, |
412 | "discard dirty block: blocknr=%llu, size=%zu", | |
413 | (u64)bh->b_blocknr, bh->b_size); | |
d6517deb | 414 | |
ead8ecff | 415 | set_mask_bits(&bh->b_state, clear_bits, 0); |
8c26c4e2 VD |
416 | unlock_buffer(bh); |
417 | } while (bh = bh->b_this_page, bh != head); | |
418 | } | |
419 | ||
420 | __nilfs_clear_page_dirty(page); | |
421 | } | |
422 | ||
0c6c44cb RK |
423 | unsigned int nilfs_page_count_clean_buffers(struct page *page, |
424 | unsigned int from, unsigned int to) | |
0bd49f94 | 425 | { |
0c6c44cb | 426 | unsigned int block_start, block_end; |
0bd49f94 | 427 | struct buffer_head *bh, *head; |
0c6c44cb | 428 | unsigned int nc = 0; |
0bd49f94 RK |
429 | |
430 | for (bh = head = page_buffers(page), block_start = 0; | |
431 | bh != head || !block_start; | |
432 | block_start = block_end, bh = bh->b_this_page) { | |
433 | block_end = block_start + bh->b_size; | |
434 | if (block_end > from && block_start < to && !buffer_dirty(bh)) | |
435 | nc++; | |
436 | } | |
437 | return nc; | |
438 | } | |
ae53a0a2 | 439 | |
b83ae6d4 | 440 | void nilfs_mapping_init(struct address_space *mapping, struct inode *inode) |
ebdfed4d | 441 | { |
aa405b1f | 442 | mapping->host = inode; |
ebdfed4d RK |
443 | mapping->flags = 0; |
444 | mapping_set_gfp_mask(mapping, GFP_NOFS); | |
252aa6f5 | 445 | mapping->private_data = NULL; |
d611b22f | 446 | mapping->a_ops = &empty_aops; |
ebdfed4d | 447 | } |
0bd49f94 RK |
448 | |
449 | /* | |
450 | * NILFS2 needs clear_page_dirty() in the following two cases: | |
451 | * | |
452 | * 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears | |
453 | * page dirty flags when it copies back pages from the shadow cache | |
454 | * (gcdat->{i_mapping,i_btnode_cache}) to its original cache | |
455 | * (dat->{i_mapping,i_btnode_cache}). | |
456 | * | |
457 | * 2) Some B-tree operations like insertion or deletion may dispose buffers | |
458 | * in dirty state, and this needs to cancel the dirty state of their pages. | |
459 | */ | |
460 | int __nilfs_clear_page_dirty(struct page *page) | |
461 | { | |
462 | struct address_space *mapping = page->mapping; | |
463 | ||
464 | if (mapping) { | |
b93b0163 | 465 | xa_lock_irq(&mapping->i_pages); |
0bd49f94 | 466 | if (test_bit(PG_dirty, &page->flags)) { |
f611ff63 | 467 | __xa_clear_mark(&mapping->i_pages, page_index(page), |
0bd49f94 | 468 | PAGECACHE_TAG_DIRTY); |
b93b0163 | 469 | xa_unlock_irq(&mapping->i_pages); |
0bd49f94 RK |
470 | return clear_page_dirty_for_io(page); |
471 | } | |
b93b0163 | 472 | xa_unlock_irq(&mapping->i_pages); |
0bd49f94 RK |
473 | return 0; |
474 | } | |
475 | return TestClearPageDirty(page); | |
476 | } | |
622daaff RK |
477 | |
478 | /** | |
479 | * nilfs_find_uncommitted_extent - find extent of uncommitted data | |
480 | * @inode: inode | |
481 | * @start_blk: start block offset (in) | |
482 | * @blkoff: start offset of the found extent (out) | |
483 | * | |
484 | * This function searches an extent of buffers marked "delayed" which | |
485 | * starts from a block offset equal to or larger than @start_blk. If | |
486 | * such an extent was found, this will store the start offset in | |
487 | * @blkoff and return its length in blocks. Otherwise, zero is | |
488 | * returned. | |
489 | */ | |
490 | unsigned long nilfs_find_uncommitted_extent(struct inode *inode, | |
491 | sector_t start_blk, | |
492 | sector_t *blkoff) | |
493 | { | |
494 | unsigned int i; | |
495 | pgoff_t index; | |
496 | unsigned int nblocks_in_page; | |
497 | unsigned long length = 0; | |
498 | sector_t b; | |
499 | struct pagevec pvec; | |
500 | struct page *page; | |
501 | ||
502 | if (inode->i_mapping->nrpages == 0) | |
503 | return 0; | |
504 | ||
09cbfeaf KS |
505 | index = start_blk >> (PAGE_SHIFT - inode->i_blkbits); |
506 | nblocks_in_page = 1U << (PAGE_SHIFT - inode->i_blkbits); | |
622daaff | 507 | |
86679820 | 508 | pagevec_init(&pvec); |
622daaff RK |
509 | |
510 | repeat: | |
511 | pvec.nr = find_get_pages_contig(inode->i_mapping, index, PAGEVEC_SIZE, | |
512 | pvec.pages); | |
513 | if (pvec.nr == 0) | |
514 | return length; | |
515 | ||
516 | if (length > 0 && pvec.pages[0]->index > index) | |
517 | goto out; | |
518 | ||
09cbfeaf | 519 | b = pvec.pages[0]->index << (PAGE_SHIFT - inode->i_blkbits); |
622daaff RK |
520 | i = 0; |
521 | do { | |
522 | page = pvec.pages[i]; | |
523 | ||
524 | lock_page(page); | |
525 | if (page_has_buffers(page)) { | |
526 | struct buffer_head *bh, *head; | |
527 | ||
528 | bh = head = page_buffers(page); | |
529 | do { | |
530 | if (b < start_blk) | |
531 | continue; | |
532 | if (buffer_delay(bh)) { | |
533 | if (length == 0) | |
534 | *blkoff = b; | |
535 | length++; | |
536 | } else if (length > 0) { | |
537 | goto out_locked; | |
538 | } | |
539 | } while (++b, bh = bh->b_this_page, bh != head); | |
540 | } else { | |
541 | if (length > 0) | |
542 | goto out_locked; | |
543 | ||
544 | b += nblocks_in_page; | |
545 | } | |
546 | unlock_page(page); | |
547 | ||
548 | } while (++i < pagevec_count(&pvec)); | |
549 | ||
550 | index = page->index + 1; | |
551 | pagevec_release(&pvec); | |
552 | cond_resched(); | |
553 | goto repeat; | |
554 | ||
555 | out_locked: | |
556 | unlock_page(page); | |
557 | out: | |
558 | pagevec_release(&pvec); | |
559 | return length; | |
560 | } |